高二理孝

Human Activity

Effect

Deforestation

Extensive cutting down or burning the trees in forest

• Soil erosion 土壤侵蚀
• Landslides 山崩
• Flash floods 暴洪
• Climatic changes
• The loss of biodiversity
• The greenhouse effect and global warming

Urbanisation

Dumping of domestic waste as well as sewage 污水 discharge from houses

• Water pollution

Industrialisation

Industrial plants discharge industrial waste and heated waste

• Water pollution
• Thermal pollution

Burning

Open burning of rubbish, farms and forest

• Air pollution
• Greenhouse effect and global warming

Farming

Excessive use of land for farming and stock rearing

• Eutrophication
• Water pollution

Pollution

Sources → Effect

Solution

Test

Air Pollution

• Burning of fossil fuels
• Sulphur dioxide: Irritate the respiratory tract and the lining of eye besides combining with rainwater to
                               form acid rain (Sources: Large industrial boiler)
• Oxides of nitrogen: Result in respiratory diseases such as bronchitis, lung cancer, irritation of organs
                                    and acid rain (Action of bacteria on fertilizers)
• Carbon monoxide: Intervene in the transport of oxygen by red blood cells to the living cells by
                                    combining with haemoglobin (Incomplete combustion of fossil fuel)
• Lead: Retards the mental development and production of cells (Vehicle exhaust fumes)
• Hydrocarbon: Result in growth defect and cancers
• Fine particulate matters: Irritate the respiratory tract and lower the rate of photosynthesis in plants
• Carbon dioxide: Result in an increase in the temperature of Earth’s atmosphere and global warming
• Chlorofluorocarbons: Cause ozone depletion and global warming
• Use low sulphur content fuels
• Use unleaded petrol
• Reduce the use of fossil fuels
• More efficient burning of fuels in well designed furnaces
• Stop open burning
• Cleaning up emissions from power stations and industrial plants with scrubbers
• Cleaning up emissions from vehicle exhausts through the use of catalytic converters

Air Pollution Index
(API)

Pollution

Sources → Effect

Solution

Test

Water Pollution

• Control the use of fertilizers
• Use biological pest control methods
• Treat sewage before it enters rivers
• Prevent farm slurry from entering rivers and ponds
• Use biodegradable detergents with low phosphate   content
• Use copper pipes instead of lead pipes in plumbing

Biochemical oxygen demand (BOD)

• Mount of oxygen utilized by microorganism to oxidize all organic matter in one litre of water
• The higher the BOD value, the more polluted the water as the dissolved oxygen level decreases
• BOD 指数↑
  污染指数↑
  氧气溶解度↓
  • Eutrophication: Artificial nutrient enrichment of an aquatic system with organic material or inorganic  
                               nutrients, causing an excessive growth of aquatic plant life 富营养化

1. Nutrients from fertilizers flow into bodies of water
2. Growth of algae increases (Algal bloom)
3. Surface of water covered by algae and block sunlight, the plants in the water unable to carry out photosynthesis and die; aquatic animals lose their food sources and habitats
4. When the algae die, decomposing organisms  especially saprophytic bacteria use up oxygen
   (Aerobic bacteria)
5. A depletion in oxygen results in an increase in biochemical oxygen demand (BOD)

含氮肥料进入河水  → 藻类大肆繁殖→ 导致阳光不能进入水→ 水中植物不能进行光和作用
→ 水中动物失去食物来源→ 水中生物死亡→ 分解者分解生物尸体 → 大量氧气被消耗→ BOD指数↑

• Control the use of fertilizers by
  

Pollution

BOD Test

Water Pollution

• Aim                              : To investigate the level of pollution in several water samples from different sources
• Problem statement   : What is the level of pollution in several different sources of water?
• Hypothesis                 : Drain water is the most polluted, river water less polluted and pipe water is the cleanest of the three
• Variables
  Manipulated               :Source of water
  Responding                : Time for the methylene blue to turn colourless
  Constant variable      : Volume of water sample, volume of methylene blue used
• Apparatus                   : 250 ml reagent bottles with stoppers, beakers, syringes and a stopwatch
• Materials                     : Methylene blue solution, sample of drain water , sample of pipe water, and sample of river water
• Technique                   : To record the time taken for methylene blue solution to decolourise by using stopwatch

• 1 ml of methlyne blue solution

  syringe

  Procedure:
  
  
  – Pipe water; B – Drain water; C –

• Precaution                  : The methylene blue solution must be added at the base of the water samples to avoid being oxidized by atmospheric oxygen
• Presentation of data  :

Pollution

Sources → Effect

Solution

Test

Thermal pollution

• Due to the release of excess heat into the enviromnet
• Discharge of hot water from factories, nuclear reactors, electric power stations

1. The level of dissolved oxygen decreases as oxygen becomes less soluble in the water
2. Some aquatic organisms die
3. This causes a change in the species composition of the aquatic ecosystem
4. The increase in temperature increases the rate of decomposition of organic matter
5. Thus, increase the BOD value
6. The concentration of oxygen in the water decreases, causing the death of aquatic organisms

• Control the amount of hot water discharged from industrial plants and power stations

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Noise pollution

• Excessive noise in the environment and disturbs the tranquility of life
• Sources:
  Automobiles and airplanes, Construction sites, Entertainment sites, Operating machines

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